Thanks for contacting us.
1/ Try to disable “Advanced Layout” in XStore–>Theme Options–>WooCommerce(Shop)–>Cart/Checkout.
2/ Please provide temporary wp-admin access via the Private Content, so we can check the settings of the Header Builder on your site.
Create an account via Dashboard (Users > Add new) with administrator role http://prntscr.com/s3rc9m > provide us with username and password via the Private Content area http://prntscr.com/s5mao7 You can use any email for it.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.